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International Journal of Engineering & Technology, 7 (4.38) (2018) 379-382
International Journal of Engineering & Technology
Website: www.sciencepubco.com/index.php/IJET
Research paper
Increasing the Accuracy of Measuring the Resistance of the
Grounding System with an Electrodeless Method
Maia Tugushi, Boris Karasiev, Gizo Partskhaladze, Madona Loria, Gocha Chavleshvili
Batumi State Maritime Academy, associate professor maritime engineering faculty, Batumi, Georgia; Batumi Shota Rustaveli State
University, assistant professor of technology faculty, Batumi, Georgia, e-mail-maia_tugushi@mail.ru
electrical engineer, Batumi Shota Rustaveli State University, teacher of technology faculty, Batumi, Georgia,e-mail- kara-boris@yandex.com
Batumi Shota Rustaveli State University, professor of technology faculty, Batumi, Georgia, e-mail-gizopar5@yahoo.com
Batumi Shota Rustaveli State University, assistant professor of technology faculty, Batumi, Georgia, e-mail-madona.loria@bsu.edu.ge
Batumi Shota Rustaveli State University, associate professor of technology faculty, Batumi, Georgia, e-mail-gocha.chavleshvili@bsu.edu.ge
Abstract
Recently, electrodeless methods of measuring the resistance of grounding devices have appeared, with the help of special clamps. But a large
methodological error limits the possibility of their use, especially when rationing low resistances. The article shows the possibility to improve
the accuracy of electrodeless measurement methods using commercially available measuring instruments.
In electrical installations of telecommunication networks of buildings, structures and industrial enterprises, the form of the AC voltage signal
of the industrial supply network (~220V, 50/60Hz) can be differ greatly from the sinusoidal for short periods of time. The causes of
distortions are usually associated with a sudden change in the network load [1], for example, when you turn on a powerful electric motor,
furnace, welding machine, etc.
The occurrence of impulse overvoltages and interference caused by electromagnetic effects (lightning, switching, radio frequency and others)
on low-voltage networks, not only leads to failure of electrical installations, cables, switchboards, but also to damage the terminal equipment
and malfunction. This is due, primarily, to the saturation of modern buildings and structures with information, telecommunications and other
digital equipment, which has a very low level of protection against impulse overvoltages and interference. All this makes it necessary to carry
out appropriate protective measures. To reduce interference, it is necessary to perform a separate (working) ground loop, the resistance of
which must be measured and periodically monitored.
There are devices that allow an electrodeless method to monitor and evaluate the resistance of the ground loop. But these devices have a
greater measurement error than devices that measure the resistance of the earth electrode method.
The article deals with existing instruments (CA6410, MZC-303E) which can evaluate the resistance of the earth electrode and the possibility
of increasing the accuracy of the measurement with the help of special current clamps is shown. Using a predetermined value of neutral
impedance, the measurement error of the calculated resistance of the earthing switch can be determined with great accuracy.
Keywords: measurement accuracy, earthing/grounding, resistance, electrodless method.
1. Introduction
The main parameters of electrical safety include: insulation
resistance, resistance of grounding devices (GD), and contour
resistance "phase-zero" [2]. Periodic monitoring and measurement of
electrical safety parameters is a mandatory requirement of safety
regulations and rules ([3], [4], [5], [6]) for the technical operation of
electrical installations ([7], [8], [9]).
For these purposes, the world market offers a large selection of
devices that guarantee the necessary accuracy of measurements,
provided that the user meets certain operating conditions.
Unfortunately, these conditions are not always feasible.
In particular, instruments for measuring the resistance of the
grounding device, in addition to the performance of the climatic
conditions of operation, require the specific placement of current and
potential electrodes (metal pins jammed into the ground) relative to
the investigated ground contour (depending on the geometric
dimensions of the circuit) and set the maximum permissible earth
resistance of the electrodes themselves (depending on the resistivity
of the soil in which they are placed).
In the central part of any city, where the saturation of buildings and
underground utilities is high, solid asphalt or concrete, the
application of these devices becomes impossible.
2. Main text
2.1. Problem Definition
In such cases, reckoning methods are used to determine the
resistance of the GD, given the known geometric dimensions of the